/*
 * jPOS Project [http://jpos.org]
 * Copyright (C) 2000-2015 Alejandro P. Revilla
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.jpos.iso.channel;

import org.jpos.iso.*;

import java.io.IOException;
import java.net.ServerSocket;

/**
 * ISOChannel implementation suitable for OASIS Ltd &copy; hosts<br>
 * (four ASCII characters header indicating message length)
 *
 * @author apr@cs.com.uy
 * @version $Id$
 * @see ISOMsg
 * @see ISOException
 * @see ISOChannel
 */
public class ASCIIChannel extends BaseChannel {
	/**
	 * Public constructor (used by Class.forName("...").newInstance())
	 */
	public ASCIIChannel() {
		super();
	}

	/**
	 * Construct client ISOChannel
	 *
	 * @param host server TCP Address
	 * @param port server port number
	 * @param p    an ISOPackager
	 * @see ISOPackager
	 */
	public ASCIIChannel(String host, int port, ISOPackager p) {
		super(host, port, p);
	}

	/**
	 * Construct server ISOChannel
	 *
	 * @param p an ISOPackager
	 * @throws IOException
	 * @see ISOPackager
	 */
	public ASCIIChannel(ISOPackager p) throws IOException {
		super(p);
	}

	/**
	 * constructs a server ISOChannel associated with a Server Socket
	 *
	 * @param p            an ISOPackager
	 * @param serverSocket where to accept a connection
	 * @throws IOException
	 * @see ISOPackager
	 */
	public ASCIIChannel(ISOPackager p, ServerSocket serverSocket)
			throws IOException {
		super(p, serverSocket);
	}

	/**
	 * @param len the packed Message len
	 * @throws IOException
	 */
	protected void sendMessageLength(int len) throws IOException {
		if (len > 9999)
			throw new IOException("len exceeded");
		else if (len < 0)
			throw new IOException("invalid length");
		serverOut.write(ISOUtil.zeropad(len, 4).getBytes());
	}

	/**
	 * @return the Message len
	 * @throws IOException, ISOException
	 */
	protected int getMessageLength() throws IOException, ISOException {
		int l = 0;
		byte[] b = new byte[4];
		while (l == 0) {
			serverIn.readFully(b, 0, 4);
			try {
				if ((l = Integer.parseInt(new String(b))) == 0) {
					serverOut.write(b);
					serverOut.flush();
				}
			} catch (NumberFormatException e) {
				throw new ISOException("Invalid message length " + new String(b));
			}
		}
		return l;
	}
}

